This invention relates to an apparatus for fixing a raster coordinate point within a flat data representation and for producing an electrical data signal corresponding to the coordinate point, particularly for placing in the vicinity of a keyboard for a computer system or the like.
Known apparatuses of this type are formed e.g. by a control stick movable in two coordinate directions. In addition, foils operable by finger pressure and equipped with capacitive switches, as well as optically released light pencils are known. Finally, apparatus exist, which can be operated by use of a flat data representation, the movement being sensed in a rolling ball and converted into electrical signals. All these known apparatuses suffer from the disadvantage that they do not permit, or only inadquately permit the giving of absolute settings with respect to the coordinate directions and the values for the individual coordinates and generally it is also not ensured that the set coordinate point remains unchanged when operation by the user is interrupted.
Computers can be advantageously used by blind and partially sighted people, because communication with the computer takes place from a fixed operating position, with a spatially constant keyboard and on the basis of fixed diagrams. However, they have problems in that, in conventional installations, the computer output is in the form of a printout or is shown on a screen. To enable blind and partially sighted people to perceive this output, devices have been developed which convert the data output into synthetic speech or reproduce portions of the screen picture on a greatly increased scale. Although this fundamentally makes it possible to perceive the data output, considerable difficulties have resulted for the following reasons.
For efficient working, it is necessary for blind and partially sighted people to use programs developed for sighted users. These programs frequently work in such a way that the output is based on perception by use of a screen, i.e. the screen shows operating lists for the input (menus), data input forms (masks) or working tables for dynamic calculation representations (worksheets). These representations are used in such a way that by use of the keyboard, the operator feeds in information and the computer gives an answer either in the form of a short character sequence, e.g. an error message, or as an output covering most of the screen, or e.g. in the case of a list-type output covers more than one complete screen side, so that after reading over the first screen side, the output of the following side must be operated. In the latter case of a more comprehensive screen output, the operator will frequently not read the content of the information fed out completely and in order and will instead only seek out those parts of interest to him by diagonal scanning with the eye. However, this is not possible for blind and partially sighted persons, who can only use a conventional speech or large picture output. They have to receive all the information in order, which is extremely disadvantageous with regards to the ease of acquisition of the stored data and with regards to the working speed.
In addition, output ways are known, which supply the data fed out in Braille form. This script is scanned by feel, by a blind person, so that, for him to communicate with the computer for reading the output, he must remove his hands from the keyboard and then, for entering further data, must orient himself again with respect to the keyboard. In addition, such a printout is naturally relatively complicated.
On the basis of this, a further partial problem of the invention is to so develop an apparatus of the aforementioned type that blind and partially sighted people can rapidly and easily be provided with computer output information intended for screen display, the apparatus being very reliable, inexpensive to manufacture and compact.
According to the invention, there is provided apparatus as a working aid for blind and partially sighted people for communication with a computer system with a keyboard and with a screen output for a screen as an output device for determining a raster coordinate point of said screen output and for producing an electrical data signal corresponding to said coordinate point, said apparatus including a device for converting the read-out data into speech or as a large picture, wherein at least two data call-up devices are provided capable to call up the data corresponding to a certain coordinate point in the form of two only end position-stable sliders movable independently of one another in two coordinate directions perpendicular to one another, thus defining by their relative coordinate position said certain coordinate point, one of said sliders being arranged above or below and one of said sliders being arranged to one of the sides of said keyboard, a position detection device being provided at each slider for supplying an electrical signal corresponding to the displacement path of this slider along one of the coordinate directions being subdivided in raster sections, and said call-up devices having a data call-up release device to call up said converted read-out data corresponding to said certain coordinate point at a desired moment.
The displacement paths of the sliders thus cover a surface corresponding to the flat data representation, so that a raster coordinate point of this surface is fixed by the position of the two sliders movable along two coordinate directions perpendicular to one another. The information call-up release devices on each slider make it possible e.g. to call up the information content of the particular raster coordinate point, if both devices are simultaneously operated, or the information content of an associated row or column when operating only one of these devices. As a result of this construction according to the invention, the blind or partially sighted person has in particular the possibility of quickly looking over a page of text in the same way as a sighted person.
This is insofar important for those persons as frequently pages are not completely filled especially if they contain columns of numbers or the like. Blind persons and partially sighted persons have no survey about such a page and it takes them a lot of time to get an idea of the contents of such a page. According to the invention it is easy for such people to find very quickly those raster coordinate points which contain a desired information. Furthermore, it is important for such persons to quickly locate again a certain point to continue the read-out of information, e.g. after an interruption of work. As the sliders according to the invention are end position-stable the blind persons may feel for the sliders, can find them easily and can continue to work to read out information exactly from the point where the work was interrupted.